Now that software-defined networking (SDN) has emerged from the honeymoon phase and has entered the real world, where the more difficult work of deployment is happening, it’s worth tracking some progress. The buzz on the street is that the SDN market is taking longer to develop than we'd like, but a look beneath the covers reveals that SDN is being targeted for some pragmatic use cases in both enterprise and service provider networks.

Yes, it's true that a broad, sweeping adoption of SDN and network virtualization (NV)) has not yet arrived, but it's being adopted by forward-thinking operators and enterprises. Some of the market leaders have reported recent growth. For example, VMware, which is a good proxy for the market, says that its Q1 revenue doubled for its NSX network virtualization business. VMware says it now has 340 customers running NSX software in production.

Recently, I've been interviewing a number of service provider, cloud, and enterprise SDN enthusiasts to see what they think of SDN and NV. They told me that SDN deployments are challenging, not because the technology isn't valuable, but because of challenges they have testing the interoperability of the software. While these users are still sold on the concept of virtualization of their infrastructures (two large service providers and a cloud operator told me this), they said the ecosystem still needs to develop.

For those that do take the plunge, our research indicates that things are going relatively well. From a survey of SDxCentral.com users in last year's “Network Virtualization in the Data Center” report, more than 75 percent of customers that deployed a network virtualization solution in the data center had a positive experience – with 60 percent having moderate success and 16 percent having “extreme” success.

Other research backs this up. In late 2015, research firm IHS interviewed major operators that have deployed or plan to deploy SDN by the end of 2016 and discovered that 85 percent of survey respondents expected data center network operating expenses to decrease significantly by the second year of SDN deployment.

In the enterprise, some high-profile deployments have targeted network security and visibility.

NEC, one of the market leaders in SDN, says it had 650 customer deployments as of fiscal year 2015. NEC got into SDN early in the game, partnering with Japanese telecom providers such as NTT, which were among the earliest adopters of SDN technology.

In another example, stateside, Cornell University’s computing and information scientists deployed NEC’s SDN and NV virtualization technology, which is based on OpenFlow. Scott Yoest, IT director of Computing and Information Science at Cornell’s College of Engineering, says that SDN technology gives the network better performance and flexibility by allowing traffic flows to be redirected dynamically.

REANZZ is New Zealand’s own national research network. It’s running one of its enterprise networks on an SDN switching system, with the goal of providing an open networking environment. REANZZ says this project could pave the way for SDN to be implemented by its members, which include all New Zealand universities, Crown Research Institutes, and leading institutes of technology and polytechnics.

One of the largest enterprise deployments we have identified to date happened at Tribune Media, where 141 applications were migrated to an SDN infrastructure in five months, according to David Giambruna, Tribune CIO. He says one of the drivers of adopting a virtualized environment was better security and flexibility. Tribune uses VMware's NSX solution.

In yet another example, technology firm Géant, whose network connects more than 10,000 research institutions such as the CERN physics lab in Switzerland, said it is deploying SDN using a combination of Infinera’s packet-optical technology, Corsa Technology’s programmable switching and routing platform, and the Open Network Operating System (ONOS) SDN controller.

These are just some examples of many deployments backed up by results of our research, which indicates that users are looking to SDN and NV technology to provide more flexibility, scalability, and security in their operating environments.

Early patterns in SDN deployment indicate that both in the service provider and enterprise markets, the top use cases for network virtualization are in the data center and campus/branch virtual networks. Let's take a look at a few of the most common use cases we have seen.

Data center virtual networks: Organizations want to slice and dice their infrastructures to create a number of isolated, virtualized networks, so that they have the flexibility to support the needs of their different customers or clients, lines of business, and/or departments.

Microsegmentation of the data center: SDN and NV can be used to deploy security controls, such as virtual firewalls, that segment the network and manage access to resources across different tenants within the data center network. Organizations can even segment the network to control access to individual apps, providing additional security – a trend in the industry known as “microsegmentation.”

Centralized management of the distributed network: By using an SDN overlay solution, an organization can manage all its branch locations from a central point – giving it valuable insight on usage and traffic patterns. SDN can also be used to automate campus and branch network operations and maximize the utility of network resources.

Infrastructure-as-a-service: Cloud and service providers are offering on-demand network function services that customers can scale up or down as needed to move workloads to the cloud.

In summary, SDN isn't moving slowly because it’s unsuccessful – it’s moving slowly because it’s still new. The technology represents the biggest shift in networking architecture in 20 years. At the same time, the move to SDN for both service providers and enterprises requires a large-scale evaluation of their business and IT strategies going forward.

If you look at what folks such as Google, Amazon, and Microsoft Azure have done to provide a virtualized cloud platform using technology that is key to the NV and SDN market, it's clear they've had massive success. People like the cloud because it has all the benefits of SDN: flexibility and application portability.

While there's no doubt that the vast body of SDN startups and technology providers will not all survive, it's clear that some key uses cases have traction and that NV is alive and well in both the service provider and enterprise segments of the market.